The cylindrical superstructures are composed of silver nanoparticles with V-shaped amphiphilic arms. The short rod-like and spherical assemblies are made of gold nanoparticles with the same V-shaped amphiphilic arms. The self-assembly occurs upon slow addition of water to solution of nanoparticles in organic solvent called tetrahydrofuran. The resulting mixture is then dialyzed against pure water in order to remove organic solvent and obtain a pure aqueous solution of the superstructures (they remain in water without any precipitation, just like micelles).